When a carrying table or a locating table which uses a free ball bearing is used, a carried item can be moved or rotated in any horizontal direction and frictional resistance against the carried item is very small. Accordingly, the free ball bearing is employed for a manufacturing process required to reliably prevent damage or secure high accuracy in locating (for example, [Patent Document 1]). For example, in a machining line of a substrate (forming a layer, applying a resistor, exposing, etching and the like), a detailed carried item may be a glass substrate, such as mother glass for display of an FPD /(Flat Panel Display), and a silicon substrate (wafer) for electronic parts, such as a semiconductor device or a semiconductor package.
In this process, a bearing unit of the present invention may be disposed in: a processing room (processing chamber) of a vacuum device that processes a substrate; a vacuum chamber (vacuum room) such as a load-lock chamber disposed to locate a substrate around the inlet of the vacuum device; or a clean room. In this case, the bearing unit can be very useful for carrying, supporting, and locating a workpiece (goods and conveyed item).
The carrying table using the free ball bearing is used for various objects, such as a manufacturing line or a machining line of steel plates, a manufacturing line of architectural materials, and a carrying line of cardboard-packed carried items.
In the carrying equipment, a stopper that hits against the item, a cushion, and a guide member in contact with the item may be provided separately from the free ball bearing to stop or decelerate movement of the item in the middle of carrying. Recently, a configuration disposed in the free ball bearing and that can apply a braking force to the item in the middle of carrying has been proposed (for example, Patent Document 2). Carrying equipment using the free ball bearing has the advantage of not using a stopper, a cushion, or a guide member.